This application relates to a gas turbine engine, wherein an accessory gear box is split into at least two portions driven by the main gas turbine engine, and positioned within a nacelle.
Gas turbine engines are known, and typically include a fan delivering air into a bypass duct, and into a core engine. Air in the core engine passes through a compressor which compresses the air and delivers it into a combustor section. The air is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors.
The turbine rotors are driven to rotate, and drive the fan and compressor. In addition, power from the turbine rotors rotation is utilized to generate electricity, and to drive accessories to support the operation of the gas turbine engine.
As an example, pumps for supplying liquid to the gas turbine engine are driven as accessories.
Another accessory is a starter. The starter is typically provided with a fluid drive, which drives turbine rotors to rotate the starter, and the starter begins to rotate other accessories and the gas turbine engine thru a drive shaft. The same drive shaft operates to drive other accessories, all through a gear box.
One known location for the accessory gear box is between an inner and outer wall of the nacelle. Typically, a single gear box has been provided at one circumferential location in the nacelle. This has resulted in the radial thickness of the nacelle being relatively large.
Recently a gear reduction has been provided between a turbine that drives the fan and the fan rotor. One result of this gear reduction, is that the fan rotor can be made much larger, and the volume of bypass air can be greatly increased to increase propulsion. To increase the fan diameter, the inner diameter of a nacelle also increases. With such an increased inner diameter, it becomes desirable to limit the radial thickness of the nacelle.